What is equivalent to 3 ounces of 80- proof vodka?

Three ounces of 80-proof vodka is equivalent to approximately 1.5 ounces of pure alcohol, since 80-proof vodka contains 40% alcohol by volume. This means that for every 1 ounce of vodka, there is 0.4 ounces of pure alcohol. Therefore, if you're comparing it to other Alcoholic Beverages, 3 ounces of 80-proof vodka is roughly equivalent to 12 ounces of beer (at around 5% alcohol by volume) or 5 ounces of wine (at around 12% alcohol by volume).